Vehicle seat

ABSTRACT

A seat back pad 70 has a groove 73 for tucking a skin material therein, formed at borders between a central portion 71 and side portions 72. A hole (slot hole 74) is formed in a bottom of the groove 73 along the groove 73. A tuck-in wire 76 for tucking the skin material in includes a plurality of tuck-in portions 76A provided along the groove 73, and a connecting portion (detour portion 76B) detouring around the hole and connecting the tuck-in portions 76A. With this configuration, when an upper body of an occupant P subsides into a seat back S2 in a rear-end collision of a vehicle, the central portion 71, defined by the groove 73 as a border, is easily and sufficiently moved rearward relative to the left and right side portions 72. Furthermore, the tuck-in wire 76 is not exposed through the hole, and thus adhesion between the seat back pad 70 and the tuck-in wire 76 can be improved.

This application is a Continuation of U.S. Ser. No. 15/877,943, filed onJan. 23, 2018, now U.S. Pat. No. 10,144,317 which is a Continuation ofU.S. Ser. No. 15/095,534, filed on Apr. 11, 2016, now U.S. Pat. No.9,896,005 which is a Continuation of U.S. Ser. No. 14/717,713, filed onMay 20, 2015, now U.S. Pat. No. 9,346,379 which is a Continuation ofU.S. Ser. No. 14/591,599, filed on Jan. 7, 2015, now U.S. Pat. No.9,061,613 which is a Continuation of U.S. Ser. No. 13/995,774, filed onJun. 19, 2013, now U.S. Pat. No. 8,955,907 which is a National StageApplication of PCT/JP 2011/079914, filed on Dec. 22, 2011, whichapplications are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a vehicle seat such as a car seat, andparticularly to a vehicle seat configured to absorb a shock given to aneck of an occupant in a rear-end collision.

BACKGROUND ART

In a rear-end collision of a car that occurs when a rear end of your caris struck by another car or when a rear end of your car which is beingreversed strikes another car or a construct, a head of an occupantseated on a seat cushion of a car seat would largely tilt back byinertia, and in reaction thereto, the neck of the occupant would likelybe given a large shock. With this in view, the car seat is commonlyprovided with a headrest for receiving the head of the occupant from aback side so as to absorb a shock given to the neck of the occupant in arear-end collision of the car.

Herein, an occupant seated on a seat cushion and driving a car is, inmany cases, postured in an in-seat position with a head slightly apartfrom the headrest to the front, and many of other passengers not drivingthe car also have similar in-seat positions. When a car in which anoccupant/passenger is seated in such a posture is rear-ended, the headof the occupant would tilt slightly to the rear before being received,and would go tilted back to the front in reaction thereto, so that itsbenefit of absorbing a shock given to the neck of the occupant would bereduced.

Against this backdrop, there are proposed a vehicle seat and a seat backdevice which are configured such that in a rear-end collision of thecar, an upper body of an occupant tending to move rearward by inertia iscaused to subside into a seat back disposed at his/her rear side so thatthe head of the occupant is swiftly received by the headrest (e.g., seePatent Literatures 1, 2).

A vehicle seat described in Patent Literature 1 includes apressure-receiving member connected rearward-movably to a seat backframe, as a member for receiving an upper body of an occupant by meansof a seat back pad (seat back cushion) within a seat back. A seat backdevice described in Patent Literature 2 includes a sheet-like elasticmember corresponding to the pressure-receiving member described inPatent Literature 1.

In the vehicle seat described in Patent Literature 1 and the seat backdevice described in Patent Literature 2, the pressure-receiving member(sheet-like elastic member) moves together with the seat back pad to therear relative to the seat back frame when the rear-end collision of avehicle causes a rearward motion load to be imposed on an occupant andthus presses an upper body of the occupant against the seat back. As aresult, the upper body of the occupant subsides into the seat back,allowing the head of the occupant to be swiftly received by theheadrest; in this way, the shock be given to the neck of the occupantcan be absorbed.

On the other hand, a vehicle seat having a seat structure in which aside air bag device is provided is generally known (e.g., see PatentLiterature 3). The structure disclosed in this Patent Literature 3 issuch that an insert wire (tuck-in wire) for attaching a seat skin insidea vertical groove formed in the seat back pad is embedded in a seat backpad.

CITATION LIST Patent Literature

-   Patent Literature 1: JP 2010-179748 A-   Patent Literature 2: JP 2010-254126 A-   Patent Literature 3: JP 10-76084 A

SUMMARY OF INVENTION Technical Problem

The vehicle seat described in Patent Literature 1 and the seat backdevice described in Patent Literature 2 do not have any specialstructure adopted such that the upper body of an occupant is allowed tosubside into the seat back sufficiently in a rear-end collision of acar.

The structure in which an insert wire is embedded in a seat back pad hasa problem that if there are many portions in the seat back pad fromwhich the insert wire is exposed to outside, the seat back pad would besusceptible to damage at the edges of the seat back pad adjoining thewire.

The present invention is made in view of the technical background asdescribed above, and a challenge to be taken up is to provide a vehicleseat which allows an upper body of an occupant to subside into a seatback sufficiently in a rear-end collision of a vehicle to effectivelysuppress tilting-back of a head of the occupant so that a shock to begiven to his/her neck can be sufficiently absorbed, and in whichadhesion between a tuck-in wire and a seat back pad is improved.

Solution to Problem

A vehicle seat configured to solve the aforementioned challengeaccording to the present invention comprises a seat cushion, a seat backcovered with a skin material and incorporating left and right sideframes, a headrest, a pressure-receiving member connectedrearward-movably to the left and right side frames, a seat back pad withwhich at least a front surface of the pressure-receiving member and aseat back frame are covered, and tuck-in wires embedded in the seat backpad. This vehicle seat is configured such that a rearward motion loadreceived from an upper body of an occupant seated on the seat cushionand acting on the seat back causes the pressure-receiving member to moverearward to cause the upper body of the occupant to subside into theseat back. The seat back pad includes a central portion configured toface a back of the upper body of the occupant and side portionsconfigured to face sides of the upper body of the occupant, the sideportions being provided continuously to the central portion, the seatback pad having a groove for tucking the skin material therein, thegroove being formed at borders between the central portion and the sideportions. In a bottom of the groove, a hole is formed along the groove.Each tuck-in wire includes a plurality of tuck-in portions providedalong the groove, and a connecting portion detouring around the hole andconnecting the plurality of the tuck-in portions.

In this vehicle seat, the rearward motion load received from the upperbody of the occupant and acting on the seat back in a rear-end collisionof the vehicle causes the pressure-receiving member to move rearwardtogether with the seat back pad relative to the seat back frame, so thatthe upper body of the occupant subsides into the seat back. In thismotion, the central portion of the seat back pad which faces the back ofthe upper body of the occupant and which is bordered with the groovehaving a hole is caused to move rearward easily and sufficientlyrelative to the side portions. Thus, the upper body of the occupant isallowed to subside sufficiently into the seat back. As a result,tilting-back of a head of the occupant is suppressed sufficiently sothat a shock which would be given to his/her neck can be sufficientlyabsorbed. Moreover, since the tuck-in wire is configured to partiallylie along the groove so as to detour around the hole, the tuck-in wireis not exposed through the hole, so that adhesion between the seat backpad and the tuck-in wire can be improved. Accordingly, damage of theseat back pad at the edges of the seat back pad adjoining the wire issuppressed.

In the vehicle seat as described above, the tuck-in wire may preferablybe embedded in a position shifted from the groove to a central portionside of the seat back pad around the hole. In this configuration, thetuck-in wire may have a two-dimensionally bent simple shape, and thusthe productivity for the tuck-in wires can be improved.

In the vehicle seat as described above, the hole may preferably bedisposed in a position outside relative to the pressure-receiving memberand inside relative to the left or right side frame with respect to alateral direction.

With this configuration, since the hole is disposed in a positionoutside relative to the pressure-receiving member and inside relative tothe left or right side frame with respect to the lateral direction, aregion in which the pressure-receiving member and the side frames areshifted relative to each other in the front-rear direction and a regionin which the seat back pad deforms substantially coincide with eachother. This makes the seat back pad easily deformable and thepressure-receiving member smoothly movable rearward.

The vehicle seat as described above may preferable comprise a connectingwire which includes two end portions connected to the left and rightside frames and a middle portion supporting the pressure-receivingmember, wherein the connecting wire includes extra-length portions bowedto deviate from an axial line connecting the two end portions of theconnecting wire, the extra-length portions being formed in left andright sections of the connecting wire between the side frames and thepressure-receiving member.

With this configuration, when the upper body of the occupant is causedto subside into the seat back, the connecting wire by which thepressure-receiving member is rearward-movably connected to the sideframes sags rearward and extends while the left and right extra-lengthportions acts as torsion springs. Accordingly, the rearward-motionstroke of the pressure-receiving member increases and thus the upperbody of the occupant subsides deeply into the seat back. As a result,the tilting-back of the head of the occupant is suppressed sufficientlyso that a shock to be given to his/her neck can be absorbedsufficiently.

In the vehicle seat with the connecting wire as described above, thehole may preferably be disposed in positions facing to the extra-lengthportions of the connecting wire. In this configuration, a region inwhich the connecting wire deforms and a region in which the seat backpad deforms coincide with each other, and thus the seat back pad and theextra-length portions are made easily deformable, so that thepressure-receiving member can be caused to smoothly move rearward.

The connecting wire may preferably be configured such that two endportions connected by the side frames are disposed in positions higherthan the middle portion supporting the pressure-receiving member. Inthis configuration, the pressure-receiving member is suspended via theconnecting wire on the side frames, and thus the pressure-receivingmember achieves a stabilized posture when it is being mounted to theseat back frame and after it has been mounted.

Assuming that the extra-length portions of the connecting wire are bowedupwardly, when the upper body of the occupant is caused to subside intothe seat back in a rear-end collision of the vehicle, the extra-lengthportions properly block shoulder regions of the occupant from subsiding,so that the occupant achieves a stabilized seat-in posture in therear-end collision.

Assuming that webbing mounting hardware for a side air bag device iswelded to at least one of the left and right side frames, it ispreferable that at least one end portion of the connecting wire isconnected to a position adjacent to a welded spot of the webbingmounting hardware. With this configuration, the rearward motion loadimposed on the pressure-receiving member is received effectively by ahigher-rigidity portion(s) of the side frame(s).

The extra-length portions of the connecting wire may preferably be bowedtoward directions away from the webbing mounting hardware welded to theside frame(s). With this configuration, the extra-length portions do notinterfere with the webbing mounting hardware, and thus the workabilityin attachment of the connecting wire is improved.

The vehicle seat as described above may comprise an upper connectingmember configured to connect an upper portion of the pressure-receivingmember to the left and right side frames, which upper connecting membercomprises a wire having a springiness. This vehicle seat may preferablybe configured to comprise a cross member disposed above thepressure-receiving member and bridging the left and right side frames,wherein the cross member comprises a rod having a rigidity higher thanthat of the upper connecting member, with a plurality of bent portionsformed therein, the bent portions being bowed downwardly relative to twoend portions fixed to the side frames.

With this configuration, the rearward motion of the shoulder regions ofthe occupant is received and blocked by the plurality of bent portionsof the cross member when the upper body of the occupant is caused tosubside into the seat back, so that the upper body of the occupantsubsides into the seat back in a safe in-seat posture with his/her backbeing hunched. As a result, the clearance between the head of theoccupant and the headrest swiftly decreases, and thus the tilting-backof the head is suppressed effectively, so that the shock given to theneck is absorbed satisfactorily.

Since the bent portions are bowed downwardly relative to the two endportions fixed to the side frames, the two end portions fixed to theside frames serve as pivots about which the bent portions deform so asto turn rearward in an intense rear-end collision; therefore, the bentportions can absorb the shock without imposing a great force on theoccupant.

The plurality of bent portions of the cross member may preferably bedisposed rearwardly relative to an initial position of thepressure-receiving member before moving rearward. With thisconfiguration, after the shoulder regions of the occupant subsideslightly into the seat back, the upper body of the occupant becomespostured with his/her back being hunched, and the head of the occupantis swiftly brought close to the headrest and received by the headrest.

Herein, the bent portions of the cross member may preferably beconfigured to comprise four bilaterally symmetrical bent portions ofwhich an inner pair of left and right bent portions is disposed withlower ends thereof located above the pressure-receiving member and anouter pair of left and right bent portions is disposed with lower endsthereof located laterally outside the pressure-receiving member abovethe pressure-receiving member. With this configuration, the rearwardmotion load given from the shoulder regions of the occupant to the seatback is received by the four bent portions in a well-balanced fashion,so that the occupant achieves a stabilized in-seat posture.

The side frames may preferably be configured to include pad shaperetainer portions each shaped like a plate jutting frontward to retainshapes of the side portions of the seat back pad, and pipe portionsprotruding upward beyond the pad shape retainer portions, wherein aplate-like bracket is fixed to the pipe portions and protrudesfrontward.

With this configuration, since the pad shape retainer portions and thebracket disposed above in the side frames serve to suppress rearwarddeformation of the seat back pad at upper and lower portions of the seatback pad when the upper body of the occupant is caused to subside intothe seat back, the occupant is likely to become postured with his/herback being hunched, and thus the central region of his/her back subsidesinto the seat back pad antecedently; therefore, the clearance betweenthe head and the headrest swiftly decreases, so that the shock given tothe neck can be absorbed.

The bracket may preferably comprise a plate member shaped like a letterU in cross section with flanges at an upper end and a lower end thereof.With this configuration, the rigidity of the bracket can be increased,and the in-seat posture of the occupant in a rear-end collision be madeeasily controllable.

The bracket may preferably be configured as a mount bracket to which anattachment is attached, such that the bracket is fixed to a laterallyinner side portion of an outer peripheral surface of the pipe portion.With this configuration, the portion at which the bracket is fixed tothe pipe portion, for example, the welded spot, is located at alaterally inner side of the pipe portion, and thus this fixed portion isnot exposed to the outside of the side frame; therefore, the attachmentcan be attached thereto from outside with ease.

The bracket may preferably be configured as a mount bracket to which anattachment is attached, and the attachment is arranged to extend alongthe pipe portion, wherein the bracket has a slot for attaching anattachment thereto, and a direction of a length of the slot is parallelto a direction of a length of the pipe portion. With this configuration,the attachment is disposed along the pipe portion of the side frame, andthe slot for allowing a positioning error which would be introduced whenthe attachment is attached extends in parallel to the pipe portion;therefore, the attachment is prevented from becoming misaligned in thefront-rear direction even when a positioning error is introduced for theattachment. Accordingly, the attachment can be arranged with the sideframe in such a manner as to achieve compactness, and the workability inattachment is improved due to allowance of the positioning error to beintroduced for the attachment.

The tuck-in wires and the pressure-receiving member may preferably haveportions overlapping each other as viewed from a front-rear direction.

With this configuration, when a load is imposed on the tuck-in wiresfrom frontward, the pressure-receiving member receives this load;therefore, unevenly balanced imposition of the load on the tuck-in wirescan be suppressed.

It may be preferably that webbing mounting hardware for a side air bagdevice is welded to at least one of the left and right side frames, andthe webbing mounting hardware is located rearwardly of the side portion.

With this configuration, the webbing mounting hardware serves tosuppress excessive deformation of the side portion toward rearward.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a car seat showing one embodiment of avehicle seat according to the present invention.

FIG. 2 is a perspective view of a seat frame incorporated in the carseat shown in FIG. 1.

FIG. 3 is a front elevation of a seat back frame shown in FIG. 2.

FIG. 4 is a perspective view of a support tab shown in FIG. 3 and itsvicinity.

FIG. 5 is a perspective view of a mount bracket shown in FIG. 2 and itsvicinity.

FIG. 6 show partially enlarged views of a side air bag device shown inFIG. 2 and its vicinity, in which (a) is a perspective view, and (b) isa side elevation.

FIG. 7 is a front elevation of a seat back pad incorporated in the seatback shown in FIG. 1.

FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7.

FIG. 9 is a sectional view of a seat back illustrated with an in-seatposture of an occupant during a normal driving operation of the car.

FIG. 10 is a sectional view of the seat back illustrated with an in-seatposture of an occupant in a moderate rear-end collision or at an earlystage in a rear-end collision.

FIG. 11 is a sectional view of the seat back illustrated with an in-seatposture of an occupant in an intense rear-end collision.

DESCRIPTION OF EMBODIMENTS

Hereafter, a description will be given of one embodiment of a vehicleseat according to the present invention with reference made to theaccompanying drawings. The vehicle seat according to one embodiment isconfigured as a car seat S arranged in a location of a driver's seat ofan automobile, for example as shown in FIG. 1. This car seat S includesa seat cushion S1, a seat back S2 and a headrest, in which a padmaterial made of a cushion material such as urethane foam is coveredwith a skin material such as a synthetic leather or a cloth.

The seat cushion S1 and the seat back S2 incorporate a seat frame F asshown in FIGS. 2 and 3. This seat frame F comprises a seat cushion frameF1 which constitutes a frame of the seat cushion S1 and a seat backframe F2 which constitutes a frame of the seat back S2. The headrest S3incorporates a headrest frame (not shown) which constitutes its frame.

The seat cushion frame F1 shown in FIG. 2 is installed, for example, ona floor for a driver's seat via slide rails SL, in such a manner thatits position in the front-rear direction is adjustable, where thedirections are designated as front-rear, left-right (lateral) andupward-downward (upper-lower) directions in view of the eyes of anoccupant assumed to be seated on the seat cushion S1 shown in FIG. 1. Alower portion of the seat back frame F2 is pivotally linked to a rearportion of the seat cushion frame F1 via a reclining mechanism RLwhereby the seat back frame F2 is rendered tiltable frontward andrearward.

The seat back frame F2 is configured in the shape of a frame with anupper frame 10, left and right side frames 20 and a lower frame 30integrally joined together by welding or the like. Inside thisframe-shaped seat back frame F2, a pressure-receiving member 40 forsupporting an upper body of an occupant in a manner that renders theupper body movable rearward is disposed.

The upper frame 10, made by bending tubing, includes a transverse pipeportion 11 and vertical pipe portions 13, 13 extending from the left andright ends of the transverse pipe portion 11, and is formed like aninverted U. A pair of left and right support brackets 12, 12 forattaching a pair of left and right headrest stays (designation byreference characters is omitted) protruding from a lower portion of theheadrest S3 are fixed to a front side of the transverse pipe portion 11by welding.

The vertical pipe portions 13, 13 are integrated with left and rightside frame main body portions 21, 21 which are continuously welded tolower portions of the vertical pipe portions 13, 13, so as to constitutethe left and right side frames 20. The side frame main body portions 21,21 are made of sheet metal, and upper portions thereof are configured towrap the vertical pipe portions 13, 13 of the upper frame 10, and areintegrally spot-welded to the vertical pipe portions 13, 13. The sideframe main body portions 21, 21 are configured to jut frontward toretain the shapes of side portions of a seat back pad which will bedescribed later, to constitute pad shape retainer portions (seepositions designated by the reference numeral 21).

The pressure-receiving member 40 is made of a sheet-like plastic plate,and an upper portion thereof is connected to the left and right sideframes 20 via an upper connecting wire 22 configured as an upperconnecting member, while a lower portion thereof is connected to theleft and right side frames 20 via a lower connecting wire 23 (see FIG.3) configured as a lower connecting member. FIG. 3 shows thepressure-receiving member 40 having a recessed portion R formed on aperipheral edge of the pressure-receiving member 40. The recessedportion R is recessed laterally inwardly relative to other portions ofthe peripheral edge of the pressure-receiving member 40.

As shown in FIG. 4, a left end portion 22A of the upper connecting wire22 is bent downward along the vertical pipe portion 13 of the upperframe 10, and the left end portion 22A of the upper connecting wire 22is wrapped with a support tab 14 fixed by welding to the left verticalpipe portion 13 of the upper frame 10, and connected to the verticalpipe portion 13.

Although not illustrated, a right end portion 22A of the upperconnecting wire 22 is also wrapped with a similar support tab 14 andconnected to the right vertical pipe portion 13 of the upper frame 10.An engageable portion (not shown) formed on a rear side of an upperportion of the pressure-receiving member 40 is engaged with a middleportion of the upper connecting wire 22, and thus the upper portion ofthe pressure-receiving member 40 is connected via the upper connectingwire 22 to the left and right side frames 20.

On the other hand, two end portions of the lower connecting wire 23 are,as shown in FIG. 3, engaged with toggle stopper mechanisms 50, 50disposed on inner sides of the left and right side frame main bodyportions 21, 21. An engageable portion (not shown) formed on a rear sideof a lower portion of the pressure-receiving member 40 is engaged with amiddle portion of the lower connecting wire 23, and thus the lowerportion of the pressure-receiving member 40 is connected via the lowerconnecting wire 23 to the left and right side frames 20.

It is appreciated that if the pressure-receiving member 40 is suspendedfrom the side frames 20 by means of the upper connecting wire 22 and thelower connecting wire 23, the posture of the pressure-receiving member40 is kept stabilized during and after the pressure-receiving member 40is attached to the seat back frame F2. In this respect, in order tostabilize the posture of the pressure-receiving member 40, the upperconnecting wire 22 and the lower connecting wire 23 are arranged suchthat the two end portions 22B (the positions of the upper portions ofthe end portions 22A led out from upper ends of the support tabs 14) atwhich the wires are connected to the side frames 20 are located inpositions higher than the middle portions thereof supporting thepressure-receiving member 40.

As shown in FIG. 3 and FIG. 6, the toggle stopper mechanisms 50, 50include pivotal link members 52, 52 that are pivotable rearward overdead points while resisting the tensions of extension springs 51, 51,and the two ends of the lower connecting wires 23 are connected to lowerends of these pivotal link members 52, 52.

In order to allow the pressure-receiving member 40 to swiftly andsmoothly move rearward when a rearward motion load of a predeterminedmagnitude or greater from the upper body of an occupant seated on theseat cushion S1 (see FIG. 1) acts on the seat back S2, the upperconnecting wire 22 and the lower connecting wire 23 are made of a wiresuch as of spring steel having a springiness.

The tensions of the extension springs 51, 51 of the toggle stoppermechanisms 50, 50 are set at appropriate tensions such that a rearwardmotion load of a predetermined magnitude or greater acting on the twoend portions of the lower connecting wire 23 will be able to cause thepivotal link members 52, 52 to pivot over the dead points without fail.

Moreover, in order to increase the rearward motion stroke of thepressure-receiving member 40, the extra-length portions 24, 24 bowed todeviate from an axial line connecting the two end portions 22B of theupper connecting wire 22 are formed in left and right sections of theupper connecting wire 22 which are located between the side frames 20and the pressure-receiving member 40 in the lateral direction. Theseextra-length portions 24, 24 are bowed upward and bent like an invertedU so as to face the back sides of the shoulder regions of the occupant.

Herein, as shown in FIG. 3, a cross member 15 made of a rod that isthicker and more rigid than the upper connecting wire 22 is provided tobridge the left and right vertical pipe portions 13, 13 of the upperframe 10 which constitute an upper portion of the side frame 20.

The cross member 15 is configured such that its central portion islocated in a position substantially as high as the two end portionsfixed to the front sides of the left and right vertical pipe portions13, 13 by welding, and in each of the sections at both sides of thecentral portion, two bent portions 16, 17 bowed downward to deviate fromthe position of its axial line (laterally extending line connecting thetwo ends of the cross member 15) are formed, respectively, in abilaterally symmetrical position.

Outer bent portions 16, 16 closer to the vertical pipe portions 13, 13,each bent in the form of a letter V with a rounded corner, have at leastlower ends thereof located laterally outside the pressure-receivingmember 40 above the pressure-receiving member 40. On the other hand,inner bent portions 17, 17, each bent in the form of a letter U withrounded corners, are located in their entireties (including lower endsthereof) above the pressure-receiving member 40.

The left and right bent portions 16, 17 are disposed slightly rearwardlyrelative to the pressure-receiving member 40 in positions facing theback sides of the shoulder regions of the occupant, and also serve toretain the shape of the rear side of the seat back pad which will bedescribed later.

These bent portions 16, 17 have rigidities such that rearward motion ofthe shoulder regions can be limited properly when the upper body of theoccupant subsides into the seat back S2, and if a great rearward motionload is received from the shoulders of the occupant, the bent portionsare caused to pivot about the axial line of the cross member 15 andundergo plastic deformation, so that the shock given to the shoulderregions of the occupant can be absorbed.

Herein, as shown in FIG. 5 and FIG. 6, a right end portion of the crossmember 15 is fixed by welding to a front side of the right vertical pipeportion 13 of the upper frame 10, and in a position directly below it, amount bracket 61 for the side air bag device 60 as one example of anattachment is fixed thereto by welding. To be more specific, the mountbracket 61 is welded to an area at a laterally inner side (i.e., leftside) of an outer peripheral surface of the vertical pipe portion 13.

The mount bracket 61, which is made of sheet metal, protrudes from thefront side of the vertical pipe portion 13 frontward along a directionin which the side frame main body portion 21 juts out. The mount bracket61 is provided with flanges 61A, 61B protruding therefrom inward atupper and lower edges thereof, respectively, to thereby have a U-shapedcross section, thus possessing a great rigidity. The mount bracket 61has a slot 61C formed therein, and the direction of the length of theslot 61C is parallel to the direction of the length of the vertical pipeportion 13. To the slot 61C of the mount bracket 61, an upper endportion of the side air bag device 60 disposed to extend along the rightside surface of the side frame main body portion 21 and the verticalpipe portion 13 is fixed through a bolt-nut arrangement BN applied froma laterally outer side.

As described above, a portion at which the mount bracket 61 is fixed tothe vertical pipe portion 13 is located at a laterally inner side of thevertical pipe portion 13, and thus the portion at which the mountbracket 61 is fixed to the vertical pipe portion 13 is not exposed tothe outside; therefore, the side air bag device 60 can be attachedthereto from outside with increased ease. Furthermore, since the sideair bag device 60 is disposed along the vertical pipe portion 13 of theside frame 20 and the slot 61C is disposed to extend in parallel to thevertical pipe portion 13, the side air bag device 60 is prevented frombeing misaligned in the front-rear direction even when a positioningerror is introduced for the attachment. Accordingly, the side air bagdevice 60 can be arranged with the side frame 20 in such a manner as toachieve compactness, and the workability in attachment is improved dueto allowance of the positioning error to be introduced for theattachment.

The side air bag device 60 includes webbing mounting hardware 62 forattaching webbing for restricting a direction of development of the airbag (not shown), to the side frame 20. This webbing mounting hardware 62is made of a rod bent in the shape of a vertically elongated letter U,and arranged to protrude to the pressure-receiving member 40 side,wherein an upper end portion thereof is fixed by welding to a positionof the vertical pipe portion 13 adjacent to a portion to which thesupport tab 14 is fixed, and a lower end portion thereof is fixed to theside frame main body portion 21.

The right extra-length portion 24 of the upper connecting wire 22described above is bowed upward (toward a direction away from thewebbing mounting hardware 62) so as not to interfere with the webbingmounting hardware 62, and a right end portion of this upper connectingwire 22 is connected to a high-rigidity portion of the vertical pipeportion 13, that is, a position adjacent to a spot at which the webbingmounting hardware 62 is welded thereto, whereby the strength ofconnection of the upper connecting wire 22 is enhanced.

As shown in FIG. 7 and FIG. 8, the seat back S2 is provided with a seatback pad 70 made of a cushion material such as urethane foam coveredwith a skin material 80 made of synthetic leather, fabric, or the like.This seat back pad 70 covers at least a front side of thepressure-receiving member 40 and the seat back frame F2 which constitutea frame of the seat back S2.

The seat back pad 70 has a configuration in which a central portion 71facing a back of an upper portion of an occupant, and left and rightside portions 72, 72 jutting out from the left and right sides of thecentral portion 71 in an obliquely frontward and outward direction arecontinuously provided, and grooves 73 for tucking the skin material 80therein are formed at borders between the central portion 71 and theleft and right side portions 72, 72. In order to allow the centralportion 71 of the seat back pad 70 to easily move rearward together withthe pressure-receiving member 40, relative to the left and right sideportions 72, 72 of the seat back pad 70, the bottoms of the grooves 73have a plurality of slot holes 74 as an example of holes piercedtherethrough and arranged along the grooves 73 (see FIG. 7, inparticular).

In the seat back pad 70 as described above, tuck-in wires 76 for tuckingthe skin material 80 in by means of hook members 75 are embedded by aninsert molding process. The tuck-in wires 76 include a plurality oftuck-in portions 76A provided along the grooves 73, and bent detourportions 76B as an example of connecting portions which detour aroundthe respective slot holes 74 and connecting the plurality of tuck-inportions 76A. The tuck-in portions 76A are embedded in the seat back pad70 in a bent state such that the tuck-in portions 76A are partiallyexposed (or slightly embedded) through a plurality of windows 77provided in the bottoms of the grooves 73. Supposing that the tuck-inwires 76 were configured to detour around the slot holes 74 to alaterally outer side (side portion 72 side), they should be bentthree-dimensionally (not in a plane) so as to be routed along thefrontwardly jutting shape of the side portion 72, but they are hereinconfigured to detour to the central portion 71 side, and can thus beconfigured to be bent in a plane, so that the productivity can beimproved. As shown in FIG. 8, the tuck-in wires 76 have a portionoverlapping the pressure-receiving member 40 as viewed from a front-reardirection. Therefore, when a load is applied to the tuck-in wires fromthe front, the pressure-receiving member receives this load, so thatunevenly balanced imposition of the load on the tuck-in wires can besuppressed.

Herein, in order to make it possible to effectively transmit a rearwardmotion load generated when the upper body of an occupant moves rearward,from the central portion 71 of the seat back pad 70 to the wholepressure-receiving member 40, the grooves 73 and the slot holes 74 aredisposed in positions outside relative to the pressure-receiving member40 and inside relative to the left or right side frame 20 with respectto the lateral direction. In order to make it possible to transmit therearward motion load from the central portion 71 of the seat back pad 70to the extra-length portions 24 of the upper connecting wire 22, a pairof left and right slot holes 74 disposed in the highest positions amongthe plurality of slot holes 74 are arranged in positions facing theextra-length portions 24 of the upper connecting wire 22 (see FIG. 3).

The webbing mounting hardware 62 is disposed rearwardly of the sideportions 72.

Next, referring to a car seat S configured as one embodiment of avehicle seat according to the present invention, its operation andadvantageous effects will be described. During a normal drivingoperation of a relevant car in which the car seat S shown in FIG. 1 isinstalled as a driver's seat, in many cases, an occupant P seated on theseat cushion S1 is usually postured in an in-seat position with his/herhead slightly separate frontward from the headrest S3, as shown in FIG.9.

When the relevant car with the occupant P having such an in-seat postureis rear-ended by another car or the rear end of the relevant car beingreversed strikes another car or a construct, a rearward motion load of apredetermined magnitude or greater received from the upper body of theoccupant P and acting on the seat back S2 causes the pressure-receivingmember 40 to move rearward together with the seat back pad 70 relativeto the seat back frame F2. Accordingly, the upper body of the occupant Psubsides into the seat back S2 as shown in FIG. 10. During this time,the upper body of the occupant P becomes curved with his/her back beinghunched, after the shoulder regions of the occupant P subside slightlyinto the seat back S2, because the bent portions 16, 17 of the crossmember 15 are disposed slightly rearwardly relative to thepressure-receiving member 40; thus, the head of the occupant can beswiftly brought close to the headrest S3, and received by the headrestS3.

Furthermore, when the upper body of the occupant P subsides deeply intothe seat back S2 according to the rear-end collision load, the left andright bent portions 16, 17 of the cross member 15 and the left and rightupwardly bowed extra-length portions 24, 24 of the upper connecting wire22 operate together in harmony so as to receive and suppress therearwardly moving shoulder regions of the occupant P. Therefore, in anintense rear-end collision, as shown in FIG. 11, the upper body of theoccupant P subsides into the seat back S2 while keeping his/her safein-seat posture with his/her back being hunched. In case that therearward motion load received from the shoulder regions of the occupantP by the left and right bent portions 16, 17 is extraordinary great, thebent portions 16, 17 are caused to pivot about the axial line of thecross member 15 and undergo plastic deformation, so that the shock givento the shoulder regions of the occupant P can be absorbed.

When the upper body of the occupant P subsides into the seat back S2,the left and right extra-length portions 24, 24 of the upper connectingwire 22 warp rearward while acting as a torsion spring, and extendgreatly; therefore, the rearward motion stroke of the pressure-receivingmember increases, and the upper body of the occupant P subsides moredeeply into the seat back S2. Herein, the upper connecting wire 22 isarranged in such a manner that the right end portion thereof isconnected to a position adjacent to a high-rigidity portion of the rightvertical pipe portion 13 of the upper frame 10, that is, a portion towhich the webbing mounting hardware 62 of the side air bag device 60 isfixed by welding. Therefore, the upper connecting wire 22 caneffectively receive the rearward motion load on the pressure-receivingmember 40. Since the extra-length portions 24, 24 are disposed inpositions facing the slot holes 74, a region in which the upperconnecting wire 22 deforms when the pressure-receiving member 40 movesrearward and a region in which the seat back pad 70 deforms at the sametime coincide substantially with each other, and thus the seat back pad70 and the extra-length portion 24 are easily deformable, so that therearward motion of the pressure-receiving member 40 is rendered smooth.

Furthermore, when the upper body of the occupant P subsides into theseat back S2, the side frame main body portions 21 which constitute padshape retainer portions and the mount bracket 61 for the side air bagdevice 60 fixed to the vertical pipe portion 13 which mount bracket isprovided above the side frame main body portion 21 are configured tooperate in harmony so as to constrain the upper and lower portions ofthe both side portions of the seat back pad 70 to some extent, thussuppressing the rearward deformation of these portions; therefore, theseat back pad 70 is easy to deform so that its midsection in the heightdirection thereof deforms rearward without undue strain. Accordingly, itbecomes likely that the rearward motion load is transmitted from thecentral portion 71 of the seat back pad 70 to the pressure-receivingmember 40 entirely without fail, so that the upper body of the occupantP subsides into the seat back S2 sufficiently, and the clearance betweenthe occupant P and the headrest S3 swiftly decreases.

In addition, when the upper body of the occupant P subsides into theseat back S2, the central portion 71 of the seat back pad 70 which facesthe back of the upper body of the occupant P moves rearward easily andsufficiently relative to the left and right side portions 72, 72 of theseat back pad 70, which are defined therefrom by the borders at thegrooves 73 in which a plurality of the slot holes 74 are formed.Accordingly, it becomes likely that the rearward motion load istransmitted from the central portion 71 of the seat back pad 70 to thepressure-receiving member 40 entirely without fail, so that the upperbody of the occupant P subsides into the seat back S2 sufficiently.However, since the webbing mounting hardware 62 is disposed rearwardlyof the side portion 72, excessive rearward deformation of the sideportion 76 is suppressed.

Consequently, according to one embodiment of the car seat S, thetilting-back of the head of the occupant P can be suppressedsufficiently and effectively, moreover, the head of the occupant P canbe received by the headrest S3 sufficiently and effectively, and theshock to be given to the neck of the occupant can be reducedsufficiently and effectively. Furthermore, since the rearward motionload given from the shoulder regions of the occupant P and acting on theseat back S2 is received by the left and right bent portions 16, 17 ofthe cross member 15 in a well-balanced fashion, the occupant P can bekept in a stabilized in-seat posture.

Since the tuck-in wire 76 detours around the slot holes 74, the tuck-inwire 76 is not exposed through the slot holes 74, so that exposedportions of the tuck-in wire 76 is reduced and thus adhesion betweentuck-in wire 76 and the seat back pad 70 is improved, and damage of theseat back pad 70 at the edges of the seat back pad 70 adjoining thetuck-in wire 76 is suppressed.

Since the extra-length portions 24 are bowed toward directions away fromthe webbing mounting hardware 62, interference of the extra-lengthportions 24 with the webbing mounting hardware 62 is prevented, and thusthe workability in attachment of the upper connecting wire 22 isimproved.

Although a description has been given of a car seat S as one embodimentof a vehicle seat according to the present invention, the vehicle seataccording to the present invention is not limited to the one embodimentof the car seat S, and the configurations may be modified whereappropriate. For example, a car seat of a bucket type may be applicablewhich includes no reclining mechanism RL and comprises a seat cushionS1, a seat back S2 and a headrest S3 that are integrally constructedtogether.

The vehicle seat according to the present invention may be configured asa seat for a ship or for an aircraft.

The number of the bent portions 16, 17 may not be limited to the totalfour as in an illustrated embodiment in which the bent portions arebilaterally symmetrically arranged, but may be two or three.

The extra-length portion 24 in one embodiment is illustrated to have anupwardly bowed U-shape (like an inverted U), but may alternatively havea frontwardly or rearwardly to bowed shape or a downwardly bowed shape.The two end portions of the connecting wire 22 which are connected tothe side frames 20 may be disposed in a position lower than the middleportion supporting the pressure-receiving member 40.

The tuck-in wire 76 in one embodiment is configured to detour around theslot holes 74 toward a laterally center side, but may be configured todetour toward a laterally outer side.

In the above-described embodiment, the side air bag device 60 isillustrated as an example of an attachment, but a motor or a sensor maybe adopted as an attachment.

The invention claimed is:
 1. A vehicle seat comprising a seat cushion, aseat back and a headrest, the seat back incorporating a seat back frame,a seat back pad, a connecting member, and a pressure-receiving member,the seat back frame including left and right side frames disposedseparate from each other and a lower frame connecting lower portions ofthe left and right side frames, the pressure-receiving member beingconnected rearward-movably to the left and right side frames via theconnecting member, wherein at least a front surface of thepressure-receiving member and the seat back frame are covered with theseat back pad, wherein the seat back pad includes a central portionconfigured to face a back of an upper body of an occupant and sideportions configured to face sides of the upper body of the occupant, theside portions being provided continuously to the central portion, theseat back pad having grooves formed at borders between the centralportion and the side portions, wherein each of the grooves has a bottomin which a slot hole extending through the seat back pad is formed, andwherein the slot hole is so disposed as not to overlap the lower frameas viewed from a front side.
 2. The vehicle seat according to claim 1,wherein the slot hole is disposed above the lower frame.
 3. The vehicleseat according to claim 1, wherein the slot hole is so disposed as notto overlap the pressure-receiving member as viewed from the front side.4. The vehicle seat according to claim 3, wherein the slot hole is in alaterally outer position relative to the pressure-receiving member, witha laterally innermost edge thereof being farther from a center of theseat back than a laterally outermost end of the pressure-receivingmember.
 5. The vehicle seat according to claim 3, wherein the slot holeis disposed within a space defined between a horizontal plane containingan uppermost end of the pressure-receiving member and a horizontal planecontaining a lowermost end of the pressure-receiving member.
 6. Thevehicle seat according to claim 1, wherein at least one other slot holeextending through the seat back pad is formed in the bottom of each ofthe grooves and so disposed as not to overlap the lower frame as viewedfrom the front side.
 7. The vehicle seat according to claim 6, furthercomprising webbing mounting hardware which is fixed to the seat backframe and to which webbing provided to restrict a direction ofdeployment of an airbag is attached.
 8. The vehicle seat according toclaim 7, wherein at least one slot hole is so disposed as not to overlapthe webbing mounting hardware as viewed from the front side.
 9. Thevehicle seat according to claim 7, wherein at least one slot hole isdisposed in a lateral position closer to a center of the seat back in alateral direction than a lateral position of the webbing mountinghardware.
 10. The vehicle seat according to claim 7, wherein at leastone slot hole is disposed at a height different from a height at whichthe webbing mounting hardware is disposed.